The present invention generally relates to a linear bearing for support of a sliding shaft or the like and, more specifically, to a compliant linear bearing having elastomeric and thermoplastic compounds and a helically wound wave spring to achieve the desired physical and functional properties.
Most linear actuators require guidance and support of an output shaft or tube assembly as the free end moves a load from a fully retracted to a fully extended position. Conventional linear bearings and guides are either expensive, using precision roller or ball bearing supports, or are very inexpensive sleeve type bearings that are either slightly oversize to effect a clearance fit and dimensional variation, or are split to accommodate size variations in the mounting base.
U.S. Pat. No. 4,799,653 discloses a shock and vibration control mechanism for radial attenuation of shock and vibration between two concentric rings, tubes or sleeves separated by a radial corrugated sheet. The patent is silent to issues surrounding axial or linear motion, and only addresses radial motion between concentric rings, tubes or sleeves.
U.S. Pat. No. 6,113,275 discloses a bearing having a bearing body 1, made of low-slip plastic, and a slit 2, extending along its entire axial length. The sliding zone of the bearing body 1 is split into several webs 3, extending in the axial direction of the bearing body 1, whose inner radial surfaces 4 create the sliding surface that comes into contact with the shaft. The webs 3 are connected to each other by means of flexible film bridges 6, so that the slit 2 can be opened or closed under deformation of the film bridges 6. This allows the bearing body 1 to be mounted on, and removed from, the shaft in a radial direction. The bearing of this patent relies on the use of a separate external housing to support the bearing body, adding cost and complexity to the bearing design.
As can be seen, there is a need for an improved linear bearing having, in a single device, long life, low cost, and minimal maintenance concerns. Such an improved linear bearing should provide the necessary guidance with minimal loss in power consumption. The improved linear bearing should not only extend the useful life of the shaft and bearing housing, but also the life of components that require proper alignment to minimize wear and load concentrations, such as associated gears and bearings.